ScienceShot: Saber-Tooth Tigers Add Powerful Arms to Their Arsenal

Don't get too distracted by those teeth. It turns out the saber-tooth tiger's (Smilodon fatalis) real strength is in its arms. Researchers x-rayed fossils of saber-tooth limbs (left, inset) and compared them with the bones of 29 other cat species, including the extinct American lion and a present-day tiger (middle and right, inset). As they report online today in PLoS ONE, saber-tooth forelimbs have an outer layer of dense bone that is, given their leg length, about 15% thicker than expected. The researchers suggest that the saber-tooth developed this strong shell by pinning down struggling prey with its arms. And that helped it get its next meal without risking damage to those long pearly whites.

See more ScienceShots.